We are studying closed sequential sampling plans (sampling plans for which there is a reasonable limit to the amount of data which might possibly be required) for hypothesis testing problems. We have studied and compared several such plans for one parameter problems. Our findings indicate that sequential plans which might possibly require 1.5 - 2.5 times as much data a fixed sample size plan may be expected to reduce the amount of data required by 50% or more. We are currently studying closed sequential sampling plans for problems involving several parameters.